Search for the ultrafast Meissner effect in driven YBa₂Cu₃O_6.48

Resonant excitation of certain phonon modes in high-Tc cuprates has been shown to induce THz optical properties reminiscent of superconductivity far above the equilibrium transition temperature. In this work, we search for a possible expulsion of a statically applied magnetic field in the photo-induced state, a response that would amount to an ultrafast Meissner effect. We make use of the Faraday effect in a magneto-optical crystal adjacent to the sample to reconstruct the strength of the magnetic field surrounding the photo-excited material. We study how the measured field expulsion depends on temperature and external magnetic field, characterizing the magnetic properties of the non-equilibrium state.